An investigation into the variables affecting the distribution of plants in a woodland area

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Introduction

Biology Coursework An investigation into the variables affecting the distribution of plants in a woodland area. Introduction. I will be carrying out my investigation in Whomerley wood. Whomerley wood is an ancient wood, created in the 16 th century, 400 years ago. Initially Whomerley wood seems to be largely made up of bramble and the trees consist mainly of Hornbeam, with a number of Oaks, Ash and Silver Birch trees, consequently the woodland looks to be a fairly sheltered and shaded place in the patches where the trees were growing. On the woodland floor though, there were numerous patches of Bluebells, Dog's mercury, Wood millet and Wood melleck. Make note how to identify the different plants. The woodland is coppiced on a rotation system, where one acre of trees per 15- 25 years are cut, giving them a small trunk remaining. This produces a smaller diameter wood, therefore giving other plants light and space to grow. This can be seen in the wood, and over time, on the trunks a shrub (explain what layers are) layer will start to grow. The idea of coppicing affects some of the areas factors of distribution of plants because it provides more light and space for smaller plants, i.e. dog's mercury, so they will not be competitively excluded. This also affects when they grow, because bluebells have adapted to their environment in Whomerley wood, and they start to develop in the early spring, where most of the trees surrounding them are bare. This means that the bluebells have light (through the bare tree branches) and less competition for the nutrients in the soil. Variables/Factors The factors that will affect the distribution of plants in a wood are: (information found in "Biology G.C.S.E. ...read more.

Middle

I am going to investigate the distribution of bluebells and bramble in the wood because they are two different plants. Bramble is quite an overpowering plant and the bluebell has had to adapt to this. I will be comparing the results to the light intensity as well. Prediction I think that the higher the light intensity, the more bramble coverage in the quadrat. I think this because with more light available, photosynthesis can happen quicker so more glucose will be produced which means bramble will have more sugars to use for growing compared to if it was in a shaded area. I think that because the season I am investigating in is summer, there will be little bluebell coverage. I think this because in summer the trees leaves are thick and close together and so little light are let onto the floor. I think that if the bramble is lifted slightly, we will be able to see the remains of the bluebell as it grows in the spring time when the trees have none or little leaves so light is let out onto the woodland floor. Because in spring it is lighter on the floor than in the summer under the shade of the trees, there is less competition for light between the Bramble and the Bluebell in spring, so this is when the Bluebells have their chance to grow. The hypothesis I will use is "the higher the bramble cover values the lower the bluebell cover values" and I will see how the light connects in this hypothesis. Fair Testing It is difficult to make this investigation a fair test, as it is not under a laboratory condition. ...read more.

Conclusion

This made the co ordinates not entirely random, as they were not carried out accurately. Once the quadrat was on the woodland floor, there was no accurate way available to us to record the percentages of coverage, so we had to estimate, which was inaccurate, but we did use the same person to estimate the percentage all the way through so at least we had some continuity. As the investigation was carried out outside, it was difficult to keep all of the factors the same like the temperature, the light intensity (we found there would be a few minutes where the sun would go behind a cloud so the light intensity would drop) and the shelter (the wood was mostly covered by trees, but sometimes there was a small gap in the trees from time to time). But as the results were accurate when comparing theories in other resources, these inaccuracies must have been very small and therefore would not have affected the investigation. The investigation is fairly reliable, but it could be more reliable if a more accurate way of measuring the percentage of plants per quadrat was available and the investigation was done in laboratory conditions (e.g. if an area was created in a greenhouse where all other the factors could be controlled). I could extend the investigation by taking into account the tree density in the surrounding area and how its shade affects the light density and therefore the distribution of both the Bramble and the Bluebell. I could also carry out the investigation in different acres of the wood to see if the pattern is consistent and reliable. I could see whether the coppicing makes a difference and I could see whether the pattern would be the same in different plants like the Oak trees and Dog's mercury. ...read more.

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